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PubMed2001

Comparison of 5-day, short-course gatifloxacin therapy with 7-day gatifloxacin therapy and 10-day clarithromycin therapy for acute exacerbation of chronic bronchitis.

BACKGROUND: The ideal duration of antibiotic therapy for acute exacerbation of chronic bronchitis (AECB) remains controversial. OBJECTIVE: This study compared short-course, 5-day gatifloxacin treatment with standard 10-day clarithromycin treatment in patients with AECB; 7-day gatifloxacin therapy was a secondary comparator. METHODS: This was a multicenter, prospective, randomized, double-blind study in which adult outpatients with AECB were randomized to 1 of 3 treatment groups: 5 days of gatifloxacin, 7 days of gatifloxacin, or 10 days of clarithromycin. Clinical cure and microbiologic eradication rates were determined 7 to 14 days after the completion of antibiotic treatment. RESULTS: A total of 527 patients with AECB were enrolled and treated with study drug (174, gatifloxacin 5-day; 175, gatifloxacin 7-day; 178, clarithromycin 10-day). Most patients (82%) had type 1 (severe) exacerbations, and a bacterial pathogen was isolated from pretreatmer, sputum samples in 59% of patients. The overall clinical cure rates among clinically evaluable patients were comparable between groups: 89% (135/151 patients) in the gatifloxacin 5-day group; 88% (136/154) in the gatifloxacin 7-day group; and 89% (145/163) in the clarithromycin 10-day group. The 95% CIs for the differences in response rates were -6.1 to 7.0 for gatifloxacin 5-day versus clarithromycin, -8.9 to 5.0 for gatifloxacin 7-day versus clarithromycin, and -5.5 to 8.0 for gatifloxacin 5-day versus 7-day. These observations did not appear to be affected by use of corticosteroids or smoking status, type of exacerbation, or duration of current episode. The microbiologic eradication rate among microbiologically evaluable pathogens was >90% in all treatment groups. No clinically meaningful differences were noted in the incidence of drug-related adverse events. CONCLUSION: Short-course, 5-day gatifloxacin therapy in patients with AECB resulted in clinical cure and microbiologic eradication rates comparable to those of standard 7- and 10-day therapies.

Acute Disease↗
PubMed2003

Randomized, open-label, parallel-group, multicenter study of the efficacy and tolerability of IV gatifloxacin with the option for oral stepdown gatifloxacin versus IV ceftriaxone (with or without erythromycin or clarithromycin) with the option for oral stepdown clarithromycin for treatment of patients with mild to moderate community-acquired pneumonia requiring hospitalization.

BACKGROUND: Empiric therapy for community-acquired pneumonia (CAP) requires the use of antibiotics with activity against a broad spectrum of respiratory pathogens and suitable pharmacokinetic properties to simplify IV-to-oral step-down therapy switches. OBJECTIVE: The aim of this study was to compare the efficacy and tolerability of IV gatifloxacin with the option for oral stepdown gatifloxacin with a standard regimen of IV ceftriaxone (with or without erythromycin or clarithromycin) with the option for oral stepdown clarithromycin in patients with mild to moderate CAP requiring hospitalization. METHODS: In a randomized, open-label, parallel-group, multicenter study, adults with CAP received 7 to 14 days of treatment with either IV gatifloxacin 400 mg QD with the stepdown option or IV ceftriaxone 1 or 2 g QD (with or without erythromycin 0.5 or 1 g QID or clarithromycin 500 mg BID) with the stepdown option. RESULTS: One hundred seventy adults with CAP were included in the study. IV gatifloxacin was stepped down to oral gatifloxacin in 90.6% (7785) of patients; IV ceftriaxone was stepped down to oral clarithromycin in 87.1% (7485) of patients. Among clinically evaluable patients (n = 153), cure rates at 1 to 3 days after treatment were 97.4% in the gatifloxacin group (7476) and 90.9% in the ceftriaxone group (7077), with a 95% CI for the difference (-3.7% to 19.1%) indicating statistical equivalence. In patients in whom pathogens were isolated from pretreatment sputum cultures, bacteriologic eradication rates were 100.0% (2929) and 90.9% (3033), respectively. Both regimens were well tolerated; treatment-related adverse events occurred in 27.1% (2385) and 21.2% (1885) of patients, respectively. CONCLUSIONS: In the population studied, treatment with IV gatifloxacin with an option for oral stepdown gatifloxacin was as effective for achieving clinical cure as IV ceftriaxone (with or without concomitant IV erythromycin or clarithromycin) with an option for oral stepdown clarithromycin. Both regimens were well tolerated.

Administration, Oral↗
PubMed2005

Effect of gatifloxacin ophthalmic solution 0.3% on human corneal endothelial cell density and aqueous humor gatifloxacin concentration.

PURPOSE: To evaluate the effect of gatifloxacin ophthalmic solution 0.3% (Zymar, Allergan, Inc., Irvine, CA, USA) on corneal endothelial cell density and morphology and to measure gatifloxacin penetration into aqueous humor. METHODS: This was a single-center, open-label clinical study. Ten patients undergoing standard cataract surgery and 20 nonsurgical subjects instilled gatifloxacin 0.3% four times per day for 2 days, then every 10 min for 1 hr on the third day (the surgery day for the cataract patients). Corneal endothelial cells were counted using noncontact specular microscopy. Anterior chamber fluid was withdrawn from the surgical patients, and the gatifloxacin concentration was quantified by high-pressure liquid chromatography. RESULTS: Baseline endothelial cell counts (mean +/- SD) were 2400 +/- 442 in the surgical group and 2520 +/- 212 in the nonsurgical group. The mean differences from baseline 1 hr after the last dose of gatifloxacin 0.3% were -51 +/- 213 (p = 0.23) in the surgical group and -7 +/- 150 (p = 0.42) in the nonsurgical group. In the nonsurgical group, the mean difference from baseline 3 weeks after the last dose was 18 +/- 147 (p = 0.71). The mean concentration (+/- SD) of gatifloxacin in aqueous humor was 1.26 +/- 0.55 microg/ml. CONCLUSIONS: A preoperative, prophylactic course of gatifloxacin 0.3% ophthalmic solution did not significantly affect endothelial cell density or morphology, while meaningful drug concentration was achieved in the aqueous humor.

Administration, Topical↗
PubMed2005

The successful treatment of gatifloxacin-resistant Staphylococcus aureus keratitis with Zymar (gatifloxacin 0.3%) in a NZW rabbit model.

PURPOSE: To determine whether gatifloxacin-resistant S. aureus (Gat-R-Sa) keratitis could be successfully treated with topical Zymar (gatifloxacin 0.3%) in a rabbit model. DESIGN: Experimental animal study. METHODS: Two separate studies were performed each using two clinical isolates of Gat-R-Sa, with MICs of 12 and 64 mug/ml to gatifloxacin. Study 1 consisted of four treatment groups (Zymar, Quixin [levofloxacin 0.5%], Ciloxan [ciprofloxacin 0.3%], and saline). Study 2 consisted of Zymar, cefazolin 50 mg/ml, vancomycin 50 mg/ml, and saline. Rabbits were infected intrastromally with 2,000 cfu in both eyes. Topical therapy began after four hours, every 15 minutes for 5 hours. After therapy, the eyes were graded for clinical signs of infection (blepharitis, conjunctivitis, iritis, corneal edema, and corneal infiltrates), and the corneas were homogenized to determine viable bacterial counts. RESULTS: Study 1: for both isolates, Zymar-treated eyes demonstrated significantly lower clinical scores compared with Ciloxan and saline, and significantly decreased the number of viable bacteria recovered compared with all groups. Study 2: for both isolates, Zymar and cefazolin demonstrated significantly lower clinical scores compared with vancomycin and saline. Zymar, cefazolin, and vancomycin significantly decreased the number of viable bacteria recovered compared with the saline control. CONCLUSIONS: We demonstrated the "Proof of Principle" that in vitro antibiotic resistance, based on CLSI standards, does not always correlate with in vivo treatment failure in the eye. An aggressive treatment regimen with Zymar appears to overcome in vitro resistance, resulting in the successful treatment of Gat-R-Sa infections in the NZW rabbit keratitis model.

Animals↗
PubMed2002

Gatifloxacin: a review of its use in the management of bacterial infections.

UNLABELLED: Gatifloxacin is an 8-methoxy fluoroquinolone antibacterial agent. The drug has a broader spectrum of antibacterial activity than the older fluoroquinolones (e.g. ciprofloxacin) and shows good activity against many Gram-positive and Gram-negative pathogens, atypical organisms and some anaerobes. Notably, gatifloxacin is highly active against both penicillin-susceptible and -resistant strains of Streptococcus pneumoniae, a common causative pathogen in community-acquired pneumonia (CAP), acute sinusitis and acute bacterial exacerbations of bronchitis. Gatifloxacin is absorbed well from the gastrointestinal tract (oral bioavailability is almost 100%). Therefore, patients can be switched from intravenous to oral therapy without an adjustment in dosage. High concentrations of gatifloxacin are achieved in plasma and target tissues/fluids. Gatifloxacin has a long plasma elimination half-life, thus allowing once-daily administration. Few clinically significant interactions between gatifloxacin and other drugs have been reported. In patients with CAP, clinical response rates in recipients of intravenous/oral gatifloxacin 400 mg/day ranged from 86.8 to 98.0% and rates of bacterial eradication ranged from 83.1 to 100% (up to 28 days post-treatment). Gatifloxacin showed efficacy similar to that of amoxicillin/clavulanic acid, ceftriaxone (with or without erythromycin) with or without stepdown to clarithromycin, levofloxacin or clarithromycin. Gatifloxacin was as effective as clarithromycin or amoxicillin/clavulanic acid, and was significantly more effective (in terms of clinical response; p < 0.035) than 7 to 10 days' treatment with cefuroxime axetil in the treatment of acute exacerbations of chronic bronchitis. In acute sinusitis, gatifloxacin showed clinical efficacy similar to that of clarithromycin, trovafloxacin or amoxicillin/clavulanic acid. Genitourinary infections were also successfully treated with gatifloxacin. Gatifloxacin is generally well tolerated. Its tolerability profile was broadly similar to those of comparator agents in comparative trials. The most common adverse events are gastrointestinal symptoms (oral formulation) and injection site reactions. CONCLUSIONS: Gatifloxacin has an extended spectrum of antibacterial activity and provides better coverage of Gram-positive organisms (e.g. S. pneumoniae) than some older fluoroquinolones. The drug has favourable pharmacokinetic properties, is administered once daily and is at least as well tolerated as other fluoroquinolones. Gatifloxacin is a useful addition to the fluoroquinolones currently available for use in the clinical setting and has an important role in the management of adult patients with various bacterial infections. As with other fluoroquinolones, careful control of gatifloxacin usage in the community is important in order to prevent the emergence of bacterial resistance and thus preserve the clinical value of this agent.

Animals↗
PubMed2006

Gatifloxacin acutely stimulates insulin secretion and chronically suppresses insulin biosynthesis.

Gatifloxacin can cause both hypoglycemia and hyperglycemia in both diabetic and non-diabetic patients. Gatifloxacin recently has been reported to stimulate insulin secretion by inhibition of ATP-sensitive K(+) (K(ATP)) channels in pancreatic beta-cells. Gatifloxacin-induced hypoglycemia is associated with concomitant use of sulfonylureas, and usually occurs immediately after administration of the drug. We find that gatifloxacin acutely stimulates insulin secretion from mouse pancreatic islets and that glibenclamide has additive effects on gatifloxacin-induced insulin secretion. On the other hand, gatifloxacin-induced hyperglycemia often takes several days to develop. We also demonstrate that chronic gatifloxacin treatment decreases islet insulin content by inhibiting insulin biosynthesis, which process may be associated with gatifloxacin-induced hyperglycemia. Moreover, discontinuation of gatifloxacin results in improved insulin secretory response. These data clarify the differing mechanisms of gatifloxacin-induced hyper- and hypoglycemia, and suggest that blood glucose levels should be carefully monitored during gatifloxacin administration, especially in elderly patients with renal insufficiency, unrecognized diabetes, or other metabolic disorders. Because the risk of potentially life-threatening dysglycemia is increased during gatifloxacin therapy, these findings have important implications for clinical practice.

Animals↗
PubMed2005

Comparison of gatifloxacin and levofloxacin administered at various dosing regimens to hospitalised patients with community-acquired pneumonia: pharmacodynamic target attainment study using North American surveillance data for Streptococcus pneumoniae.

This work aimed at determining the target attainment potential of gatifloxacin and levofloxacin in specific age-related patient populations such as elderly (> or =65 years) versus younger (<65 years) hospitalised patients with community-acquired pneumonia (CAP). Previously described population pharmacokinetic models of gatifloxacin and levofloxacin administration in patients with serious CAP were utilised to simulate gatifloxacin and levofloxacin pharmacokinetics. Pharmacokinetic simulations and susceptibility data for Streptococcus pneumoniae from the ongoing national surveillance study, Canadian Respiratory Organism Susceptibility Study (CROSS), were then used to produce pharmacodynamic indices of free-drug area under the curve over 24h relative to the minimum inhibitory concentration (free-drug AUC(0-24)/MIC(all)). Monte Carlo simulations were then used to analyse target attainment both of gatifloxacin and levofloxacin to achieve free-drug AUC(0-24)/MIC(all)> or =30 against S. pneumoniae in patients with CAP. Dosing regimens for gatifloxacin were 400 mg once daily (qd) administered to younger patients (<65 years) and gatifloxacin 200 mg qd to elderly patients (> or =65 years). Dosing regimens for levofloxacin were simulated as 500 mg, 750 mg and 1000 mg qd administered to elderly patients as well as younger patients. Monte Carlo simulations using gatifloxacin 400mg against S. pneumoniae yielded probabilities of achieving free-drug AUC(0-24)/MIC(all) of 30 of 96.6% for all patients, 92.3% for younger patients and 97.7% for elderly patients. When administered to elderly patients, a reduced dose of gatifloxacin 200mg qd could achieve a target attainment potential of 91.4%. Monte Carlo simulation using levofloxacin 500 mg qd yielded probabilities of achieving free-drug AUC(0-24)/MIC(all) of 30 of 92.3% for all patients, 95.7% for elderly patients compared with 72.7% for younger patients. Using levofloxacin 750 mg and 1000 mg qd had probabilities of achieving free-drug AUC(0-24)/MIC(all) of 30 of 97.0% and 98.3%, 98.1% and 99.2%, and 90.1% and 95.2% for all patients, elderly patients and younger patients, respectively. The probability of achieving free-drug AUC(0-24)/MIC(all) of 100 was low both with gatifloxacin and levofloxacin, except in the case of elderly patients receiving levofloxacin in a dose of 1000 mg qd (78.5%). We conclude that gatifloxacin and levofloxacin pharmacokinetics in elderly patients with CAP are markedly different from those of younger patients. Higher gatifloxacin/levofloxacin AUC and longer half-life (t(1/2)) values in elderly patients with CAP compared with younger patients provide better pharmacodynamic parameters (free-drug AUC(0-24)/MIC) leading to a higher probability of pharmacodynamic target attainment and improved bacteriological outcome against S. pneumoniae. Gatifloxacin 400mg qd results in a high probability of target attainment and improved bacteriological outcome against S. pneumoniae both in young and elderly CAP patients. However, gatifloxacin administered at a lowered dose of 200 mg qd in elderly patients could still be successful in producing a favourable antibacterial effect. Levofloxacin administered at a dose of 750 mg qd results in a high probability of target attainment and improved bacteriological outcome against S. pneumoniae in all patients with CAP.

Adult↗
PubMed2000

In vitro antibacterial spectrum of a new broad-spectrum 8-methoxy fluoroquinolone, gatifloxacin.

The in vitro antibacterial spectrum of gatifloxacin was compared with those of ciprofloxacin and ofloxacin. Gatifloxacin was two- to four-fold more potent than comparator quinolones against staphylococci, streptococci, pneumococci and enterococci (gatifloxacin MIC90s, < or =1 mg/L, except 4 mg/L against methicillin-resistant Staphylococcus aureus and Enterococcus faecium). Gatifloxacin was two-fold less potent than ciprofloxacin, and the same as or two-fold more potent than ofloxacin against Enterobacteriaceae (MIC90s, 0.06-0.5 mg/L against most members of the Enterobacteriaceae and < or =1 mg/L against Proteus/Morganella spp.). Relative to the comparator quinolones, gatifloxacin was two- to four-fold more potent against Providencia spp., and had good potency against Acinetobacter spp. (MIC90s, 0.25-1 mg/L). Gatifloxacin and ofloxacin had similar anti-pseudomonal potency, with corresponding MIC90s of 4, 8 and 0.25 mg/L for Pseudomonas aeruginosa, Pseudomonas fluorescens and Pseudomonas stutzeri, while ciprofloxacin had two- to eight-fold more potency. The three quinolones were equipotent against Burkholderia cepacia (MIC90s, 8 mg/L), but gatifloxacin was two-fold more potent against Stenotrophomonas maltophilia (MIC90, 4 mg/L). Gatifloxacin was highly potent (MIC90s, 0.03-0.06 mg/L) against Haemophilus influenzae, Legionella spp., Helicobacter pylori and had at least eight-fold better anti-chlamydial and anti-mycoplasma potency (gatifloxacin MIC90s, 0.13 mg/L). The higher quinolone MICs for ureaplasma (MIC90s, 4-8 mg/L) may be due to the acidic pH of the ureaplasma test medium, which antagonizes quinolones. Like other quinolones, gatifloxacin had poor potency against Mycobacterium avium-intracellulare, though it was eight- to 16-fold more potent against Mycobacterium tuberculosis (MIC90, 0.25 mg/L). Of the three quinolones, only gatifloxacin had activity against Bacteroides fragilis and Clostridium difficile. In summary, gatifloxacin is a broad-spectrum 8-methoxy fluoroquinolone that is more potent than ciprofloxacin and ofloxacin against Gram-positive bacteria, chlamydia, mycoplasma, mycobacteria and anaerobes.

Anti-Infective Agents↗
PubMed1999

Pharmacokinetics of gatifloxacin and interaction with an antacid containing aluminum and magnesium.

The pharmacokinetics of gatifloxacin (400 mg orally) and the influence of the antacid aluminum magnesium hydroxide (20 ml of Maalox 70) on the bioavailability of gatifloxacin in 24 healthy volunteers were assessed. In an open, randomized, six-period crossover study, the volunteers received either gatifloxacin alone (treatments A and D); aluminum magnesium hydroxide concomitant with gatifloxacin (treatment C); or aluminum magnesium hydroxide 2 h before (treatment B), 2 h after (treatment E), or 4 h after gatifloxacin administration (treatment F). Gatifloxacin concentrations were measured by a validated bioassay and high-performance liquid chromatography. Pharmacokinetics of a single 400-mg dose of gatifloxacin alone were characterized as follows (mean +/- standard deviation): peak concentration (Cmax), 3.8 +/- 0. 5 (treatment A) and 3.4 +/- 0.9 (treatment D) microgram/ml; time to Cmax, 1.4 +/- 0.8 (treatment A) and 1.7 +/- 0.7 (treatment D) h; area under the curve from time zero to infinity (AUC0-infinity), 33. 5 +/- 5.9 (treatment A) and 31.4 +/- 3.4 (treatment D) microgram. h/ml; urine recovery, (83 +/- 6)% (treatment A) and (84 +/- 8)% (treatment D). Comparison of the results obtained by bioassay showed a good correlation. Aluminum magnesium hydroxide administration 2 h before (treatment B) or concomitant with (treatment C) gatifloxacin decreased the Cmax by 45% (2.1 +/- 1.2 microgram/ml) or even 68% (1.2 +/- 0.4 microgram/ml) highly significantly (P < 0.01). AUC0-infinity was significantly reduced from 33.5 +/- 5.9 to 19.4 +/- 6.9 microgram. h/ml (by 42%) or even to 11.9 +/- 3.3 microgram. h/ml (by 64%) (P < 0. 01). If aluminum magnesium hydroxide was given 2 h after gatifloxacin (treatment E), there was no significant reduction of concentration in serum but AUC0-infinity was significantly reduced from 31.4 +/- 3.4 to 25.9 +/- 5.3 microgram. h/ml (18%) (P < 0.01). Aluminum magnesium hydroxide given 4 h after gatifloxacin (treatment F) showed no influence on the gatifloxacin pharmacokinetics. Therefore, the optimal time between gatifloxacin application and the intake of an aluminum-containing antacid should be 4 h.

Administration, Oral↗
PubMed2004

Urinary bactericidal activity, urinary excretion and plasma concentrations of gatifloxacin (400 mg) versus ciprofloxacin (500 mg) in healthy volunteers after a single oral dose.

In an open randomised double-crossover study 12 volunteers (six men, six women) received a single oral dose of gatifloxacin (400 mg) or ciprofloxacin (500 mg) to assess urinary bactericidal activity (in eight intervals up to 120 h) and pharmacokinetic (PK) parameters (up to 36 h). Plasma concentrations and urinary excretion were determined by HPLC with fluorescence detection, and urinary bactericidal titers (UBT) by microdilution-method, using antibiotic-free urine of each volunteer. The mean maximum plasma concentration of gatifloxacin was 3.35 mg/l and that of ciprofloxacin 2.12 mg/l. The mean (median) cumulative renal excretion of the parent drug was for gatifloxacin 81 (83)% of the administered dose within 120 h and for ciprofloxacin 43 (45)%. The UBTs, i.e. the highest two-fold dilution (antibiotic-free urine as diluent) of urine still being bactericidal, were determined for an Escherichia coli ATCC reference strain and nine clinical uropathogens with the following MICs (mg/l) for gatifloxacin/ciprofloxacin (microdilution, MHB): E. coli ATCC 25922 (0.008/0.008); E. coli 523 (0.06/0.06); Klebsiella pneumoniae 1058 (0.03/0.016); Proteus mirabilis 524 (0.125/0.016); Pseudomonas aeruginosa 561 (1/0.125); Enterococcus faecalis strains 60 an 55 (0.5/1 and 8/32); Staphylococcus aureus strains 248 and 596 (both 0.03/0.125) and S. saprophyticus Ho94 (0.125/0.25). The median UBTs measured within the first 6h for gatifloxacin were between 1:16 and 1:>or=1024 for the Gram-negative strains including P. aeruginosa and between 1:8 and 1:>or=1024 for the five Gram-positive strains. The median UBTs for ciprofloxacin were between 1:64 and 1:>or=1024 for the Gram-negative strains (incl P. aeruginosa) and between 1:1.5 and 1:768 for the five Gram-positive strains. The UBTs up to 12 < 0.05 h showed no difference (P<0.05 ) for both E. coli strains, but ciprofloxacin was superior to gatifloxacin against Klebsiella, Proteus and Pseudomonas strains and gatifloxacin was superior to ciprofloxacin against all Gram-positive strains. For the UBTs at 12-24 h, gatifloxacin was generally superior to ciprofloxacin, but showed no difference in the Proteus and Pseudomonas strains. The areas under the UBT-time-curve (AUBT) up to 120 h showed statistically significant (P ) differences between both quinolones in favour of gatifloxacin against 8 of 10 strains tested, no difference for P. mirabilis and significantly higher activity of ciprofloxacin against P. aeruginosa. In conclusion, gatifloxacin and ciprofloxacin had overall comparable initial urinary bactericidal activity with some differences for specific pathogens, some times in favour of gatifloxacin (Gram-positives) and some times of ciprofloxacin (usually Gram-negatives), suggesting that for empiric therapy a single oral dose of gatifloxacin (400mg) would be clinically equivalent to ciprofloxacin (500 mg) twice daily-in agreement with the results of a clinical study in complicated UTI performed previously [Int. J. Antimicrob. Agents (2004)].

Administration, Oral↗
PubMed2002

A multicenter, randomized, investigator-blinded study of 5- and 10-day gatifloxacin versus 10-day amoxicillin/clavulanate in patients with acute bacterial sinusitis.

BACKGROUND: Treatment guidelines for acute bacterial sinusitis recommend 10 to 14 days of therapy with amoxicillin/clavulanate, high-dose amoxicillin, cefpodoxime, cefuroxime, or a newer fluoroquinolone. OBJECTIVE: This study compared the clinical efficacy of short-course (5-day) gatifloxacin with standard 10-day regimens of amoxicillin/clavulanate or gatifloxacin in patients with a diagnosis of acute, uncomplicated maxillary sinusitis. METHODS: This was a multicenter, investigator-blinded study in adult patients (age >18 years) with physical findings, signs and symptoms (for at least 7 days), and radiographic findings indicating acute, uncomplicated maxillary sinusitis. Patients were randomized to receive gatifloxacin 400 mg once daily for 5 days, gatifloxacin 400 mg once daily for 10 days, or amoxicillin/clavulanate 875 mg twice daily for 10 days. Clinical response was assessed once between days 3 and 5 of treatment, once I to 3 days after the completion of study treatment, once 7 to 14 days posttreatment (test-of-cure visit), and once 21 to 28 days posttreatment. Safety was assessed throughout the study. RESULTS: The study enrolled 445 patients. The treatment groups were similar in terms of history of sinusitis, presenting signs and symptoms, and radiographic findings. The most common presenting symptoms were nasal congestion, sinus tenderness, and purulent nasal discharge (>90% of patients); 99% of patients had abnormal radiographic findings. At the test-of-cure visit, clinical cure rates for clinically evaluable patients in the 3 treatment groups were 74% (102/137) for 5-day gatifloxacin, 80% (101/127) for 10-day gatifloxacin, and 72% (101/ 141) for 10-day amoxicillin/clavulanate (95% CI for the difference in cure rates: 5-day gatifloxacin vs amoxicillin/clavulanate, -7.6 to 13.2; 5- vs 10-day gatifloxacin, -15.2 to 5.1; 10-day gatifloxacin vs amoxicillin/clavulanate, -2.3 to 18.1). The distribution and incidence of drug-related adverse events (AEs) were comparable between treatment groups, and the majority (>95%) were mild or moderate in severity. The most common drug-related AEs included vaginitis, diarrhea, and nausea. CONCLUSION: In this population of patients with acute, uncomplicated sinusitis of presumed bacterial origin, a short course (5 days) of gatifloxacin therapy was associated with comparable clinical cure rates and tolerability to those of standard 10-day therapy with gatifloxacin or amoxicillin/clavulanate.

Adult↗
PubMed2001

Can antimicrobial susceptibility testing results for ciprofloxacin or levofloxacin predict susceptibility to a newer fluoroquinolone, gatifloxacin?: Report from The SENTRY Antimicrobial Surveillance Program (1997-99).

A serious problem confronting clinical laboratories and hospital formulary practices is the delayed availability of approved, commercially prepared susceptibility test reagents for newer antimicrobials. A current example is gatifloxacin, a new 8-methoxy fluoroquinolone with expanded potency against many Gram-positive pathogens. This study addresses the use of "surrogate marker" fluoroquinolones to predict susceptibility for gatifloxacin. Reference broth microdilution MIC results for 29,632 strains isolated in United States medical centers (SENTRY Antimicrobial Surveillance Program, 1997-99) were used: staphylococci (9,940 strains), enterococci (2,570), Streptococcus pneumoniae (3,784), Enterobacteriaceae (10,670) and Pseudomonas aeruginosa (2,668). Gatifloxacin interpretation categories were compared to those of ciprofloxacin and levofloxacin by regression statistics and error rate bounding analyses. For the Enterobacteriaceae, the absolute categorical agreement was 97.9 to 98.7% (false-susceptible or very-major error [VME], 0.03%-0.1%) for comparisons of both ciprofloxacin and levofloxacin with gatifloxacin. P. aeruginosa testing was more problematic (higher minor error rates), but acceptable at 0.6% to 1.1% VME and a 85.7% to 89.9% overall agreement. Ciprofloxacin results used to predict gatifloxacin in Gram-positive species was almost without VME (0.0%-0.2%) because gatifloxacin was significantly superior against these species, especially for S. pneumoniae, where gatifloxacin (MIC(90,) 0.5 microg/ml) was fourfold more potent than levofloxacin (MIC(90,) 2 microg/ml). The preferred gatifloxacin predictor drug was ciprofloxacin for all species except S. pneumoniae and P. aeruginosa, where levofloxacin results had a slightly greater predictive value. Susceptibility testing results for selected currently available fluoroquinolones can be used to predict susceptibility to gatifloxacin with high confidence. Many Gram-positive cocci, however, will be categorized as false-resistant by this interim method since gatifloxacin has a 11% to 34% wider spectrum of activity compared to ciprofloxacin when testing staphylococci and enterococci. Clinical laboratories can reliably use these suggested "surrogate markers" until reliable tests for gatifloxacin become available.

Anti-Infective Agents↗
PubMed2001

Activity of gatifloxacin against strains resistant to ofloxacin and ciprofloxacin and its ability to select for less susceptible bacterial variants.

Gatifloxacin is an 8-methoxy fluoroquinolone. On quinolones, this side chain imparts increased activity against Gram-positive bacteria and enhanced killing. Gatifloxacin was tested against ofloxacin non-susceptible (ofloxacin MIC>2 mg/l) strains of Streptococcus pneumoniae (gatifloxacin MIC(90), 1 mg/l) and methicillin-resistant Staphylococcus aureus (MRSA, gatifloxacin MIC(90), 4 mg/l), and to ciprofloxacin non-susceptible (ciprofloxacin MIC>1 mg/l) strains of Escherichia coli (gatifloxacin MIC(90),>16 mg/l) and ciprofloxacin non-susceptible (ciprofloxacin MIC>0.06 mg/l) Neisseria gonorrhoeae (gatifloxacin MIC(50), 0.12 mg/l and MIC(90), 0.5 mg/l). Though gatifloxacin showed some reduced susceptibility to these populations, the MIC(50) and MIC(90) values suggest that gatifloxacin may be useful against pneumococci and some gonococcal strains not susceptible to other fluoroquinolones. Gatifloxacin did not select for less susceptible variants of MRSA and pneumococci, in contrast to the 10- to 100-fold higher selection frequencies with ciprofloxacin and ofloxacin. The single-step E. coli mutants selected by gatifloxacin and the comparator quinolones had quinolone MICs within the susceptible range. These data suggest that gatifloxacin use may hinder the development of quinolone-resistance, particularly in Gram-positive bacteria.

Anti-Infective Agents↗
PubMed2001

The pharmacodynamics of gatifloxacin and ciprofloxacin for pneumococci in an in vitro dynamic model: prediction of equiefficient doses.

Enhanced activity against Streptococcus pneumoniae is one of the putative advantages of gatifloxacin over older fluoroquinolones such as ciprofloxacin. This study examined ciprofloxacin and gatifloxacin pharmacodynamics against two differentially susceptible clinical isolates of S. pneumoniae (gatifloxacin MIC, 0.125 and 2 mg/L; ciprofloxacin MIC, 1 and 32 mg/L). The pharmacokinetics of gatifloxacin (single dose) and ciprofloxacin (two 12 hourly doses) with half-lives of 6 and 5 h, respectively, were simulated using a two-compartment dynamic model. The AUC/MIC ratios in the peripheral compartments that contain bacterial cultures varied over a four- to five-fold range, from 11 to 48 h with ciprofloxacin and from 15 to 78 h with gatifloxacin. The intensity of the antimicrobial effect (IE) increased with increasing AUC/MIC ratios in a strain-independent fashion, although different relationships of IE to log AUC/MIC were inherent for each drug (r2 0.73 for gatifloxacin and r2 0.94 for ciprofloxacin). Subsequently, the respective dose-response relationships of gatifloxacin and ciprofloxacin for a hypothetical strain of S. pneumoniae with MIC equal to the MIC50 were modelled. Based on these relationships, the equiefficient doses of gatifloxacin and ciprofloxacin were predicted for MIC50S of 0.4 and 1 mg/L, respectively. Gatifloxacin 400 mg was predicted to be equiefficient to ciprofloxacin 1400 mg. To provide the same anti-pneumococcal effect as the usual 1000 mg daily dose of ciprofloxacin, the respective daily dose of gatifloxacin could be as low as 180 mg. This in vitro study demonstrates advantages of gatifloxacin relative to ciprofloxacin in terms of the dose-dependent total antimicrobial effect.

Anti-Infective Agents↗
PubMed2005

A randomized, investigator- masked clinical trial comparing the efficacy and safety of gatifloxacin 0.3% administered BID versus QID for the treatment BID versus QID for the treatment of acute bacterial conjunctivitis of acute bacterial conjunctivitis.

PURPOSE: To compare the efficacy and safety of To compare the efficacy and safety of gatifloxacin ophthalmic solution 0.3% (Zymar) administered BID versus QID in patients with acute bacterial conjunctivitis. METHODS: In a randomized, investigator-masked clinical trial, patients diagnosed with bacterial conjunctivitis (based on signs and symptoms) received gatifloxacin either BID or QID for 5 days. Visits were scheduled at day 0, day 3, and day 5. Conjunctival cultures were taken at each visit. The clinical cure rate at day 5 was determined for the entire patient population (primary endpoint). Additionally, clinical cure at day 5 was evaluated for a population of patients defined a priori (per protocol) as being culture positive at baseline and with no substantial protocol deviations. Safety was determined through recording of adverse events. Minimal inhibitory concentrations (MIC) and susceptibility of isolates to gatifloxacin were determined using a broth dilution method. RESULTS: Patient characteristics in both the BID and QID groups (N = 104) were similar in terms NN of baseline demographics and disposition. The clinical cure rate on day 5 in the entire, intentto-treat (ITT) population was 86.5% (45/52) in the gatifloxacin BID group and 71.2% (37/52) in the gatifloxacin QID group (95% CI: [-0.03, 30.80]; p = 0.096). In both treatment groups, 5/52 patients (9.6%) reported adverse events. The most common adverse event was conjunctivitis. No serious adverse events were reported. In the a priori-defined per-protocol (PP) population, the clinical cure rate on day 5 was 95.5% (21/22) in the gatifloxacin BID group and 85.7% (18/21) in the gatifloxacin QID group (95% CI: [-7.57, 21.05]; p = 0.294). At baseline, 96.1% (98/102) of the isolates were susceptible to gatifloxacin. The overall MIC(90) (mean +/- standard error of the mean) was 0.5 +/- 1.3 microg/mL. CONCLUSION: In this study, gatifloxacin 0.3% administered BID was as effective and as safe as gatifloxacin 0.3% administered QID for 5 days for the treatment of bacterial conjunctivitis.

Acute Disease↗
PubMed2005

Hypoglycemia associated with the use of gatifloxacin.

UNLABELLED: We present the histories, clinical findings, and hospital course of three patients who developed hypoglycemia after receiving gatifloxacin. Possible mechanisms for the hypoglycemia are outlined. CASE 1: A 89-year-old diabetic male receiving glyburide was given a single dose of gatifloxacin for bronchitis. Thirteen hours later, he was found to be unresponsive with a blood glucose level of 34 mg/dL. The hypoglycemia resolved within 24 hours of stopping gatifloxacin. CASE 2: A 80-year-old nondiabetic woman with end-stage renal disease and recent surgery was treated with gatifloxacin, cefepime, and metronidazole for pneumonia. Sixteen hours later, her serum glucose level was 61 mg/dL, and over the next 24 hours was as low as 39 mg/dL. The hypoglycemia resolved within 40 hours of stopping gatifloxacin. CASE 3: A 58-year-old diabetic man receiving glyburide was admitted for myocardial infarction and renal failure. Twelve hours after receiving gatifloxacin for pneumonia, his blood glucose level was 60 mg/dL and was as low as 42 mg/dL between 2 and 22.5 hours of a second dose of gatifloxacin. The hypoglycemia resolved within 24 hours of stopping gatifloxacin. CONCLUSIONS: Gatifloxacin use may precipitate hypoglycemia in diabetic patients receiving oral hypoglycemic agents and in nondiabetic patients with chronic renal failure. Discontinuation of gatifloxacin results in improvement in glucose homeostasis.

Aged, 80 and over↗
PubMed2003

Bioavailability of gatifloxacin by gastric tube administration with and without concomitant enteral feeding in critically ill patients.

OBJECTIVE: Sequential intravenous-to-oral antimicrobial therapy with highly bioavailable antiinfective agents such as the fluoroquinolones may improve patient safety and decrease cost of infection management. However, physiologic changes associated with critical illness may alter drug absorption, distribution, and clearance, and concomitant enteral feeding may decrease fluoroquinolone bioavailability. We evaluated the effect of critical illness and concomitant gastric tube feeding on gatifloxacin bioavailability. DESIGN: Prospective, randomized, single-dose, two-way crossover, pharmacokinetic study. SETTINGA tertiary, level-one, trauma center. PATIENTS: Sixteen critically ill patients (baseline Acute Physiology and Chronic Health Evaluation II score >or=16) tolerating enteral nutrition administered by gastric tube (NG) for >or=12 hrs were randomized to receive gatifloxacin concurrently with continuous tube feeding or with interrupted tube feeds. Patients with renal insufficiency or those receiving concomitant fluoroquinolone therapy or postpyloric feeding were excluded. Patients received gatifloxacin 400 mg either by the intravenous or NG route followed by the alternative dosage form after a 72-hr washout period. MEASUREMENTS AND MAIN RESULTS: Serial serum gatifloxacin concentrations (from 5 mins to 24 hrs) were analyzed using a validated high-performance liquid chromatography method. Bioavailability was determined as the ratio of NG/intravenous area under the concentration-time curve (AUC infinity ) measured by the trapezoidal method. Although there was no difference in the bioavailability between NG (AUC infinity : 38.0 [range 20.1 to 48.5] microg x h/mL) and intravenous (AUC infinity : 39.5 [range 24.1 to 63.1] microg x h/mL, p =.60) gatifloxacin (bioavailability: 98.5% [range 61.1% to 119.7%]), a wide variability was observed in three of eight patients (>30% reduction in bioavailability). Concomitant gastric tube feeding did not affect gatifloxacin bioavailability (interrupted tube feeds: 98.5% [range 61.1% to 119.7%]; continuous tube feeding: 109.0% [range 86.2% to 142.1%]; p =.42). Neither a period nor differential carryover effect was observed. CONCLUSIONS: Although concomitant tube feeding did not affect gatifloxacin bioavailability, critical illness resulted in significant variability that may complicate the role of gatifloxacin in sequential intravenous-to-oral therapy. More research is needed to identify those patients in whom gatifloxacin bioavailability is reduced and for whom an empirical increase in gatifloxacin dose should be considered.

APACHE↗
PubMed2005

Comparison of corneal surface effects of gatifloxacin and moxifloxacin using intensive and prolonged dosing protocols.

PURPOSE: To compare the effects of the commercial formulations of moxifloxacin and gatifloxacin on rabbit corneal epithelium using two dosing protocols: high-frequency dosing for bacterial keratitis and cataract surgery prophylaxis. METHODS: Forty eyes of 20 New Zealand white rabbits were randomized to receive topical gatifloxacin, topical moxifloxacin, or no drops as controls. Eighteen eyes received 1 drop of antibiotic every 5 minutes for 15 minutes followed by 1 drop every 15 minutes for 4 hours. Twelve eyes received topical gatifloxacin or topical moxifloxacin 4 times a day for 10 days. Rabbits were euthanized, eyes enucleated, and the corneas separated, washed, and fixed; scanning electron microscopy was performed. Photomicrographs of three separate areas from the corneal apex were taken at x1200 and x3000 for each cornea. Two masked, experienced examiners then graded the corneal epithelial damage. RESULTS: In the high-frequency dosing group, mean corneal damage score for eyes treated with gatifloxacin was 1.593, that for moxifloxacin was 1.407, and control was 1.000. No statistically significant difference was found between gatifloxacin and moxifloxacin (P = 0.41), gatifloxacin and control (P = 0.14), or moxifloxacin and control (P = 0.23). In the cataract surgery prophylaxis group, mean corneal damage scores for eyes treated with gatifloxacin was 1.167, that for moxifloxacin was 1.368, and control was 1.000. No statistically significant difference was found between gatifloxacin and moxifloxacin (P = 0.23), gatifloxacin and control (P = 0.08), or moxifloxacin and control (P = 0.23). CONCLUSION: Despite differences in formulations, with short-term dosing neither gatifloxacin nor moxifloxacin appears to be toxic to the corneal epithelium in this rabbit model.

Animals↗